In order to help resolve the debate about whether speciation occurs more rapidly after an extinction event, or whether the new species have all been present before but not in sufficient numbers for fossils to have been found.

Let’s define a “fossil” as any trace older than older than 500,000 years, perhaps older then 100,000 years. (Perhaps simpler to just say “Pleistocene or Pliocene” or older).

To clarify, “panthera” is a genus, with separate species lion, tiger, jaguar, leopard. So I’m not asking for fossils of separate species, any one of the species will do. “There are currently 1258 genera, 156 families, 28 orders, and around 5937 recognized living species of mammal.”

For what percentage of modern mammal genera have fossils been found?

Bird?
Mollusc?
Insect?
Fish? (More common for freshwater fish?)
Flowering plants (including pollen)?

mollwollfumble said:

In order to help resolve the debate about whether speciation occurs more rapidly after an extinction event, or whether the new species have all been present before but not in sufficient numbers for fossils to have been found.

Let’s define a “fossil” as any trace older than older than 500,000 years, perhaps older then 100,000 years. (Perhaps simpler to just say “Pleistocene or Pliocene” or older).

To clarify, “panthera” is a genus, with separate species lion, tiger, jaguar, leopard. So I’m not asking for fossils of separate species, any one of the species will do. “There are currently 1258 genera, 156 families, 28 orders, and around 5937 recognized living species of mammal.”

For what percentage of modern mammal genera have fossils been found?

Bird?
Mollusc?
Insect?
Fish? (More common for freshwater fish?)
Flowering plants (including pollen)?

A comment on pollen. When I was doing palynopalynology, I had to be able to identify modern spores and pollen because, even using great cleaning protocols, samples often had modern contaminants.

mollwollfumble said:

In order to help resolve the debate about whether speciation occurs more rapidly after an extinction event, or whether the new species have all been present before but not in sufficient numbers for fossils to have been found.

I’m speaking from ignorance here, but anyway:

Is there such a debate?

How could the rate of speciation not be higher after an extinction event?

The Rev Dodgson said:

mollwollfumble said:

In order to help resolve the debate about whether speciation occurs more rapidly after an extinction event, or whether the new species have all been present before but not in sufficient numbers for fossils to have been found.

I’m speaking from ignorance here, but anyway:

Is there such a debate?

How could the rate of speciation not be higher after an extinction event?

There is such a debate. Based on the sudden appearance of many new fossil species after an extinction event. Examples claimed include the Cambrian “explosion” and the sudden diversification of mammals afrer the death of the dinoraurs.

I don’t think that the rate of speciation can be higher after an extinction event. But some say that small genetic differences can cause large differences in appearance.

mollwollfumble said:

I don’t think that the rate of speciation can be higher after an extinction event. But some say that small genetic differences can cause large differences in appearance.

??

Surely after an extinction event there is a much higher probability of any given genetic variation surviving, because of reduced competition, so the rate of speciation must be higher.

mollwollfumble said:

The Rev Dodgson said:

mollwollfumble said:

In order to help resolve the debate about whether speciation occurs more rapidly after an extinction event, or whether the new species have all been present before but not in sufficient numbers for fossils to have been found.

I’m speaking from ignorance here, but anyway:

Is there such a debate?

How could the rate of speciation not be higher after an extinction event?

There is such a debate. Based on the sudden appearance of many new fossil species after an extinction event. Examples claimed include the Cambrian “explosion” and the sudden diversification of mammals afrer the death of the dinoraurs.

I don’t think that the rate of speciation can be higher after an extinction event. But some say that small genetic differences can cause large differences in appearance.

Are they fossils related to deaths from the extinction event

Cymek said:

mollwollfumble said:

The Rev Dodgson said:

I’m speaking from ignorance here, but anyway:

Is there such a debate?

How could the rate of speciation not be higher after an extinction event?

There is such a debate. Based on the sudden appearance of many new fossil species after an extinction event. Examples claimed include the Cambrian “explosion” and the sudden diversification of mammals afrer the death of the dinoraurs.

I don’t think that the rate of speciation can be higher after an extinction event. But some say that small genetic differences can cause large differences in appearance.

Are they fossils related to deaths from the extinction event

I’m talking some time after that.

The Rev Dodgson said:

mollwollfumble said:

I don’t think that the rate of speciation can be higher after an extinction event. But some say that small genetic differences can cause large differences in appearance.

??

Surely after an extinction event there is a much higher probability of any given genetic variation surviving, because of reduced competition, so the rate of speciation must be higher.

On the other hand, I could claim that mutations are random and that speciation is the result of geographic isolation. Neither occur at a significantly higher rate after an extinction.

It could simply be that survivors of the catastrophe increase in number.

mollwollfumble said:

The Rev Dodgson said:

mollwollfumble said:

I don’t think that the rate of speciation can be higher after an extinction event. But some say that small genetic differences can cause large differences in appearance.

??

Surely after an extinction event there is a much higher probability of any given genetic variation surviving, because of reduced competition, so the rate of speciation must be higher.

On the other hand, I could claim that mutations are random and that speciation is the result of geographic isolation. Neither occur at a significantly higher rate after an extinction.

It could simply be that survivors of the catastrophe increase in number.

Geographical separation is not enough. You also need a vacant ecological niche, or at least a niche occupied by a less “fit” species.

Indeed, for many species you don’t even need geographic separation, a separate available niche would be sufficient, and it is these niches that are available in much greater numbers after an extinction event.

Since I wrote Pleistocene fossils, I can’t get this cartoon out of my head.

La Brea fossils. From https://en.wikipedia.org/wiki/List_of_fossil_species_in_the_La_Brea_Tar_Pits

Number of genera

* Mammals (total 52)
10 Artiodactyla
16 Carnivora
2 Chiroptera
3 Pilosa
3 Soricomorpha
3 Lagomorpha
2 Perissodactyla
1 Primates
2 Proboscidea
10 Rodentia

* Birds
11 Accipitriformes
8 Anseriformes
1 Caprimulgiformes
6 Cathartiformes
2 Ciconiiformes
13 Charadriiformes
2 Columbiformes
1 Cuculiformes
2 Falconiformes
2 Galliformes
3 Gruiformes
8 Strigiformes
34 Passeriformes
8 Pelecaniformes
5 Piciformes
2 Podicipediformes

* Reptiles, amphibians, and fish
11

* Invertebrates
>> 16

* Plants
11

So, how does that compare with LA wildlife today?

Mammals of California. Number of genera.\https://en.wikipedia.org/wiki/List_of_mammals_of_California
1 Marsupial
4 Soricomorpha
15 Chiroptera
5 Lagomorpha
31 Rodentia
20 Cetacea
19 Carnivora (excl. seals)
6 Seals
8 Artiodactyla
Total non-marine 83.

So 52 fossilised vs 82 extant mammal genera is 63%, a startlingly good fossilisation rate!

OK, there are errors here, but with a bit of luck they sort of cancel each other out.

mollwollfumble said:

La Brea fossils. From https://en.wikipedia.org/wiki/List_of_fossil_species_in_the_La_Brea_Tar_Pits

…

So 52 fossilised vs 82 extant mammal genera is 63%, a startlingly good fossilisation rate!

OK, there are errors here, but with a bit of luck they sort of cancel each other out.

• Birds
  https://en.wikipedia.org/wiki/List_of_birds_of_California
  Modern LaBrea Genus Comments
  

So that’s 283 extant genera (excluding seabirds albatross and cormorant) for the whole of California.
As against 108 La Brea genera.

That’s a 38% fossilisation rate, startlingly good for birds, especially given the small area of La Brea vs the large area of California.

La Brea may not be typical. Because so recent. Contains 300 bacterial species did I say?

Try Narracourte caves fossil assemblage. Middle Pleistocene.

https://www.biodiversitylibrary.org/page/41320507

9 large mammal genera.
12 small mammal genera.
8 bird individuals.
1 reptile genus.
1 amphibian genus.

Extant mammal genera in South Australia.

2 monotreme
31 marsupials
13 bats
10 terrestrial carnivora
9 rodents

21 fossil mammal genera to 64 extant genera.
About a 30% fossilisation rate for mammals.
Still very significant despite small fossil location relative to size of SA.

I wonder if a market exists for turning humans into fossils when your died, another burial option

Cymek said:

I wonder if a market exists for turning humans into fossils when your died, another burial option

I did hear of that, once, many years ago.

Someone was offering a fossilisation after death service for sale. It was criticised at the time for not being real fossils in that the bones were not mineralised.

The La Brea tar pits mentioned above contained a fossil wonan.